This invention relates generally to refrigerators, and more particularly, to controlling heating within such refrigerators.
Some known refrigerators include a fresh food compartment and a freezer compartment. Such a refrigerator also typically includes a refrigeration circuit including a compressor, evaporator, and condenser connected in series. An evaporator fan is provided to blow air over the evaporator, and a condenser fan is provided to blow air over the condenser. In operation, when an upper temperature limit is reached in the freezer compartment, the compressor, evaporator fan, and condenser fan are energized. Once the temperature in the freezer compartment reaches a lower temperature limit, the compressor, evaporator fan, and condenser fan are de-energized.
An ice maker may be located in the freezer compartment and operable to make ice cubes. A through-the-door ice and water dispenser may be provided to deliver ice and water to a user without the user opening the refrigerator doors. Known through the door ice dispensers include a front opening in an ice chute through which ice is dispensed. Ice dispensers typically have a duct door covering the front opening that prevents warm moist air from entering the refrigerator compartment. With such an ice dispensing apparatus, it is possible that external sweating, i.e., moisture or condensation, will appear in the ice dispenser area under high temperature or high humidity conditions. This sweating results from the relatively low temperature inside the chute and the ambient conditions to which the duct door is exposed.
Sweating has been reduced by applying heat to the areas likely to be affected by condensation. In some refrigerators this is accomplished by an electric heater positioned adjacent to the ice dispenser apparatus area. Similar heaters are positioned inside the ice dispenser apparatus or connected directly to the duct door. In other refrigerators, a hot gas loop is positioned inside the front face of the cabinet.
Electric heaters may not have an expected life as long as the refrigerator. Thus, a manufacturer may install two heaters, with the second to be used only if the first becomes inoperable. This increases the cost of all such refrigerators when only a small percentage of the second heaters will ever be needed. The use of electric heat facilitate reducing or preventing sweating requires additional energy from the refrigerator to supply the wattage to the electric heater to overcome sweating, thereby increasing energy costs. However, refrigerators must comply with government regulations with regard to energy usage. In order to comply, known refrigerators must decrease the amount of energy supplied to the electric heater resulting in decreased electric heater performance and an increase in sweating of the ice dispenser apparatus area and door duct.